assume cs:codesg, ds:datasg
datasg segment
           db 'BaSiC'
           db 'UnixF'
datasg ends
codesg segment
    start: mov  ax, datasg
           mov  ds, ax
            
           mov  cx, 5
           mov  bx, 0
        
    s:     mov  al, 0[bx]
           and  al, 11011111B
           mov  0[bx], al

           mov  al, [bx].5
           or   al, 00100000B
           mov  [bx].5, al

           inc  bx
           loop s

           mov  ax, 4c00h
           int  21H

codesg ends
end start
